SBOS743A July   2015  – May 2020 INA226-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      High-Side or Low-Side Sensing Application
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Basic ADC Functions
        1. 7.3.1.1 Power Calculation
        2. 7.3.1.2 Alert Pin
    4. 7.4 Device Functional Modes
      1. 7.4.1 Averaging and Conversion Time Considerations
      2. 7.4.2 Filtering and Input Considerations
    5. 7.5 Programming
      1. 7.5.1 Programming the Calibration Register
      2. 7.5.2 Programming the Power Measurement Engine
        1. 7.5.2.1 Calibration Register and Scaling
      3. 7.5.3 Simple Current Shunt Monitor Usage (No Programming Necessary)
      4. 7.5.4 Default Settings
      5. 7.5.5 Bus Overview
        1. 7.5.5.1 Serial Bus Address
        2. 7.5.5.2 Serial Interface
        3. 7.5.5.3 Writing to and Reading from the INA226-Q1
          1. 7.5.5.3.1 High-Speed I2C Mode
        4. 7.5.5.4 SMBus Alert Response
    6. 7.6 Register Maps
      1. Table 4. Register Set Summary
      2. 7.6.1    Configuration Register (00h) (Read/Write)
        1. Table 5. Configuration Register (00h) (Read/Write) Descriptions
      3. 7.6.2    Shunt Voltage Register (01h) (Read-Only)
        1. Table 10. Shunt Voltage Register (01h) (Read-Only) Description
      4. 7.6.3    Bus Voltage Register (02h) (Read-Only)
        1. Table 11. Bus Voltage Register (02h) (Read-Only) Description
      5. 7.6.4    Power Register (03h) (Read-Only)
        1. Table 12. Power Register (03h) (Read-Only) Description
      6. 7.6.5    Current Register (04h) (Read-Only)
        1. Table 13. Current Register (04h) (Read-Only) Register Description
      7. 7.6.6    Calibration Register (05h) (Read/Write)
        1. Table 14. Calibration Register (05h) (Read/Write) Description
      8. 7.6.7    Mask/Enable Register (06h) (Read/Write)
        1. Table 15. Mask/Enable Register (06h) (Read/Write)
      9. 7.6.8    Alert Limit Register (07h) (Read/Write)
        1. Table 16. Alert Limit Register (07h) (Read/Write) Description
      10. 7.6.9    Manufacturer ID Register (FEh) (Read-Only)
        1. Table 17. Manufacturer ID Register (FEh) (Read-Only) Description
      11. 7.6.10   Die ID Register (FFh) (Read-Only)
        1. Table 18. Die ID Register (FFh) (Read-Only) Description
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 High-Side Sensing Circuit Application
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
          1. Table 19. Configuration Register (00h) Settings for (Value = 4025h)
          2. Table 20. Configuration Register (00h) Settings for (Value = 4005h)
          3. Table 21. Mask/Enable Register (06h) Settings for and (Value = 8000h)
          4. Table 22. Alert Limit Register (07h) Settings for and (Value = 7D00)
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
    2. 11.2 Support Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.1.1 Power Calculation

The Current and Power are calculated following shunt voltage and bus voltage measurements as shown in Figure 19. Current is calculated following a shunt voltage measurement based on the value set in the Calibration Register. If there is no value loaded into the Calibration Register, the current value stored is zero. Power is calculated following the bus voltage measurement based on the previous current calculation and bus voltage measurement. If there is no value loaded in the Calibration Register, the power value stored is also zero. Again, these calculations are performed in the background and do not add to the overall conversion time. These current and power values are considered intermediate results (unless the averaging is set to 1) and are stored in an internal accumulation register, not the corresponding output registers. Following every measured sample, the newly-calculated values for current and power are appended to this accumulation register until all of the samples have been measured and averaged based on the number of averages set in the Configuration Register (00h).

INA226-Q1 ai_power_calc_scheme_bos547.gifFigure 19. Power Calculation Scheme

In addition to the current and power accumulating after every sample, the shunt and bus voltage measurements are also collected. After all of the samples have been measured and the corresponding current and power calculations have been made, the accumulated average for each of these parameters is then loaded to the corresponding output registers, where they can then be read.